User Guide

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FIGURE 14.5: TROUBLESHOOTING BLANK DISPLAY
START
Isdisplay
completely
dark?
 Verifythatdisplayisnotstillin
power‐up”process(Figure
11.2a)
 Looseormis‐wired
connectionbetweenthe
displayandterminalJ3onthe
boilercontrol
 Defectivedispla y 
Isboilercontrol’sgreen
powerlighton?
Isboilerfan
runningathigh
speed?
Is120Vpresentacross
blackandwhiteboiler
linevoltage
connectionleads?
Is24VACpresent
betweenJ8‐1andJ8‐2
(blueandyellow)
terminalsonboiler
control?
Is24VACpresent
acrosstransformer
secondary(brownand
pinkwiresatplugL3?)
Is120VAC
presentacross
blackandwhite
wiresatplugL2?
 Looseormis‐wired
connectionbetweenthe
displayandterminalJ3on
theboilercontrol
 Defectivedispla y
 Openfuseorbreakerat
mainpanel
 Looseormis‐wired
connectionbetweenmain
panelandboiler.
 Defectiveboilercontrol
 LooseplugL2
 Defective
transformer–
lookforshort
circuitin24V
wiring
 LooseplugP1
 LooseplugP3
 Looseconnection
betweenL3andJ8
SeeFigures10.5and10.6for
thelocationofconnectors
referencedhere
Y
N
Y
N
Y
N
Y
N
Y
N
Y
N
Y
N